Dental instrument



W. E. PEARL. DENTAL INSTRUMENT. APPLICATION FILED JULY 8, 19m.

Patented Feb. 8, 1921.

UNITED stares WALLER E. PEARL, OF SEDALIA, MISSOURI.

DENTAL INSTRUMENT.

Specification of Letters Patent.

Patented Feb. 8, 1921.

Application filed July 8, 1918. Serial No. 243,872.

T 0 all whom it may concern Be it known that I, WALLER E. PEARL, a citizen of the United States, residing at Sedalia in the county of Petti's and State of Missouri, have invented a new and useful Dental Instrument, of which the following is a specification.

This invention relates to dental instru ments one of its objects being to provide means for rotating delicate reamers and the like in the root canals of posterior teeth, the device being hand operated and transmitting rotary motion at a right angle.

A further object is to provide an instrument of this character which is of light weight, gives the operator a delicate sense of touch and occupies very little space in the mouth so as to obstruct the vision of the operator.

A still further object is to provide an instrument which will not slip from the hand and become lodged in the throat of the patient andalso one which will permit the use of a mouth mirror while cleaning or reaming the canals in posterior teeth.

Another object is to provide an instrument in which the power is transmitted directly from the driving shaft to the head of the reamer or other tool, thereby saving valuable space and reducing the weight of the instrument.

With the foregoing and other objects in view which will appear as the description proceeds, the invention consists of certain novel details of construction and combinations of parts which will be hereinafter more fully described and claimed, it being understood that various changes may be made in the construction and arrangement of the parts without departing from the spirit or sacrificing any of the advantages of the invention as set forth in the appended claims.

In the accompanying drawings the preferred form of the invention has been shown.

In said drawings Figure 1 is a side elevation of the instrument.

Fig. 2 is a longitudinal section therethrough.

Fig. 8 is an end view.

Fig. 4 is a detail view of the latch.

Referring to the figures by characters of reference, 1 designates the tubular casing of the instrument one end of which is counterbored as at 2 and interiorly screw thread- 1 ed while the other end terminates in a short gitudinal axis of the casing 1. This slotted portion of the elbow is closed except for a small opening 5 extending thereinto at right an les to the axis of the casing 1. k

I drive shaft or spindle 6 is mounted for rotation in the casing 1 and has a collar 7 bearing in the counterbore 2, said collar be- 111g heldin position by a threaded sleeve 8 extendlng into the counterbore from a milled nut 9 located on the end of the casing. A knob 10 is connected to the outer end of the spindle and the inner end of said splndle is formed with notches forming teeth 11 located adjacent the opening 5. The toothed end of the spindle may be held properly centered within the casing by a collar 12 thereon which engages the wall of the casing.

A latch 13 is pivotally mounted in the slot and has a laterally extending slot 14 therein the width of which is less than the diameter of the opening 5. When the latch is in one position in the slot 4 it partly covers the opening 5, as shown in Fig. 2.

The reamer or other tool to be used with the instrument, and which has been shown generally at15, is provided with a cylindri cal head 16 adapted to fit snugly within the openlng 5 and having an annular groove 17 the width of which is approximately equal to the width of the slot 4. Teeth 18 are formed on the free end of the head 16 and are designed, when the tool is in position within the opening 5. to mesh with the teeth 11. When the tool is in place the latch 13 can be swung within the slot 1 until the walls of the slot 14 in the latch enter the groove 17. thus holding the tool against withdrawal from the opening 5 and maintaining the teeth 18 in mesh with the teeth 11.

It will be apparent that the instrument can be held in one hand and while so held the knob 10 can be rotated. This will cause the spindle 6 to transmit rotary motion through the teeth 11 to the teeth 18 and tool 15. Thus the tool, although extending at right angles to the spindle, will be driven positively and will give the operator as delicate a sense of touch as though an ordinary reamer or the like were used. Because of the small size and lightness of the instrument it can be manipulated readily and, as"

before stated, 'will permit a mouth mirror to be used While the canals of the posterior teeth are being reamed or cleaned. I'mportance is attached to the fact that the.

tool has aset of gear teeth formed integral therewith as a considerable saving of space is thus effected. The tool can be: removed readily, as will be obvious, by swinging the l0 cylindrical head hearing within the opening and provided at, its inner end With: gear teeth, means for engagingthe head to hold it in the opening, a spindle in'sertible longiin; the counterbore, a second collar on the splndle, gear teeth at one end of the spindle and close to said second collar, said teeth.

meshing with the teeth on the head, a knob at one end of the spindle for rotating'it, and a nut detachably seated in the counterbore and adjustable against the first mentioned collar to thrust the spindle longitudinally and hold the teeth of the spindle in mesh with the teeth -on the head.

V In testimony that Iclaim the foregoing as my own, I have hereto afixed my sigma-' ture in the presence of two Witnesses.

V 'WALLER E. PEA it-L;

'Witnesses H. D. Dow,

J. W. PALMER. 

